A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word cactus derives, through Latin, from the Ancient Greek word κάκτος (káktos), a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Cacti occur in a wide range of shapes and sizes. They are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north, with the exception of Rhipsalis baccifera, which is also found in Africa and Sri Lanka. Cacti are adapted to live in very dry environments, including the Atacama Desert, one of the driest places on Earth. Because of this, cacti show many adaptations to conserve water. For example, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of true leaves, cacti's enlarged stems carry out photosynthesis.
Mammillaria is one of the largest genera in the cactus family (Cactaceae), with currently 200 known species and varieties recognized. Most of the mammillaria are native to Mexico, but some come from the southwest United States, the Caribbean, Colombia, Venezuela, Guatemala and Honduras. The common name "pincushion cactus" refers to this and the closely related genus Escobaria.
Cleistocactus strausii, the silver torch or wooly torch, is a perennial flowering plant in the family Cactaceae. It is native to mountainous regions of Department Tarija, Bolivia, at 1,500–3,000 m (4,921–9,843 ft).
Bergerocactus emoryi is a species of cactus, known commonly as the golden-spined cereus, golden snake cactus, velvet cactus or golden club cactus. It is a relatively small cactus, but it can form dense thickets or colonies, with the dense yellow spines giving off a velvety appearance when backlit by the sun. From April to May, yellow, green-tinged flowers emerge, which transform into reddish, globular fruit. This species is native to the California Floristic Province, and is found in northwestern Baja California and a small part of California, in San Diego County and on the southern Channel Islands. Where the Mediterranean climate of the California Floristic Province collides with the subtropical Sonoran Desert near El Rosario, hybrids with two other species of cacti are found. It is the sole member of the monotypic genus Bergerocactus, named after German botanist Alwin Berger.
Thelocactus is a genus of flowering plants in the cactus family Cactaceae. Members of the genus are native to the arid lands of Central and Northern Mexico.
Parodia is a genus of flowering plants in the family Cactaceae, native to the eastern slopes of the Andes in northwestern Argentina and southwestern Bolivia and in the lowland pampas regions of northeastern Argentina, southern Brazil, eastern Paraguay, and Uruguay. This genus has about 60 species, many of which have been transferred from Eriocactus, Notocactus and Wigginsia. They range from small globose plants to 1 m (3 ft) tall columnar cacti. All are deeply ribbed and spiny, with single flowers at or near the crown. Some species produce offsets at the base. They are popular in cultivation, but must be grown indoors where temperatures fall below 10 °C (50 °F).
Echinocactus grusonii or Kroenleinia grusonii, popularly known as the golden barrel cactus, golden ball or mother-in-law's cushion, is a species of barrel cactus which is endemic to east-central Mexico.
Echinocereus reichenbachii is a perennial plant and shrub in the cactus family. The species is native to the Chihuahuan Desert and parts of northern Mexico and the southern United States, where they grow at elevations up to 1,500 meters (4,900 ft). This cactus earned the Royal Horticultural Society's Award of Garden Merit.
Mammillaria elongata, the gold lace cactus or ladyfinger cactus, is a species of flowering plant in the family Cactaceae, native to central Mexico. Growing to 15 cm (6 in) tall by 30 cm (12 in) wide, it consists of densely packed clusters of elongated oval stems, covered in harmless yellow or brown spines, and in spring producing white or yellow flowers. It is among the most common and most variable of its genus in nature, and is a popular subject for cultivation. It has gained the Royal Horticultural Society's Award of Garden Merit.
Parodia magnifica is a species of flowering plant in the family Cactaceae, native to southern Brazil. One of several species called ball cactus, it grows to 7–15 cm (3–6 in) tall by 45 cm (18 in) broad, with heavily ribbed, spherical to columnar, spiny and hairy stems, bearing pale yellow flowers in summer. Its natural habitat is cool, dry temperate grassland at elevations of up to 800 m (2,600 ft). Populations are sparse and fragmented, and it has been designated as “Endangered” by the IUCN Red List.
Parodia tenuicylindrica is a species of cactus from the genus Parodia. The small green cacti have yellow and red-brown spines, white wool and yellow flowers. They produce yellow-green fruit, and black seeds. P. tenuicylindrica can be found growing individually in Rio Grande do Sul, Brazil.
Parodia curvispina is a species of cactus in the genus Parodia. The small, squat green plants produce yellow flowers, green fruit and black seeds. The species is found growing in Rio Grande do Sul, Brazil.
Rhipsalidopsis gaertneri, synonyms Schlumbergera gaertneri and Hatiora gaertneri, is a species of epiphytic cactus which belongs to the tribe Rhipsalideae within the subfamily Cactoideae of the Cactaceae. Together with the hybrid with R. rosea, Rhipsalidopsis × graeseri, it is known, in English speaking countries in the Northern Hemisphere, as Easter cactus or Whitsun cactus and is a widely cultivated ornamental plant. It has received the Royal Horticultural Society's Award of Garden Merit.
Parodia mammulosa is a species of succulent plant in the family Cactaceae.
Parodia schumanniana is a quite rare species of succulent plant in the family Cactaceae. The specific epithet schumanniana honors the cactus specialist Karl Moritz Schumann.
Parodia scopa, the silver ball cactus, is a species of flowering plant in the cactus family Cactaceae, native to upland southern Brazil and Uruguay. It is a ball- or cylinder-shaped cactus growing to 5–50 cm (2–20 in) tall by 10 cm (4 in) broad, with a spiny, woolly crown and pale yellow flowers in summer.
Thelocactus bicolor, the glory of Texas, is a species of flowering plant in the cactus family, widely distributed in the northern Chihuahuan Desert of the USA (Texas) and Mexico. Plants are usually solitary, but may form clumps. Growing to 50 cm (20 in) tall, it is a perennial with spiny, ribbed, succulent stems. Large daisy-like flowers, up to 8 cm (3.1 in) in diameter, are borne in summer. The petals are purplish-pink, fading to white. The inner petal tips form a circle of red surrounding a prominent yellow boss.
Gymnocalycium baldianum, the spider-cactus or dwarf chin cactus, is a species of flowering plant in the cactus family Cactaceae, native to the Catamarca Province in Argentina.
Espostoa lanata is a species of cactus of the genus Espostoa.
Echinocereus websterianus, commonly known as the San Pedro Nolasco hedgehog cactus or Webster's hedgehog cactus is a species of cactus. It is named after American philanthropist Gertrude Webster, who cofounded the Desert Botanical Garden in Phoenix, Arizona.
